Method for preventing intergranular oxidation in ternary beryllium alloys



PatentedDec. 24 ,1 040 y I i 2 225 2 4".

METHOD FOR. PREVENTING INTEBGRAN- ULAB OXIDATION IN TERNARY. BEBYL- LIUMALLOIS Richards Harrington, Schenectady, N. Y.,;as-

signor to General Electric Company, a corporation of New York v 'No Drawing. Application July 29, 1938,

Serial No. 221,976

1 Claim. (01. 148-132) The present invention relates to ternary al- If any ap reciable quantity of oxygen, carbon loys containing copper, beryllium and metal from .dioxide or water vapor ispresent in the furnace the group cobalt and chromium but more paratmosphere, intergranular oxidation of the alticularly to a method for producing such alloys loy wire or strip will takeplace. .Partially comin the form of wire or strip. Alloys or this .combustedcity gas, cracked ammonia, or substantial- 5 position are disclosed in Dahl Patent 1,847,929 ly any gaseous-medium from which oxygen, carand in Horstkotte Patent 1,957,214 and heretobon dioxide and water vapor have been removed fore have been employed to a considerable ex'- may be employed as the furnace. atmosphere. tent forged matel'ialflnd ca and 11113116 When the strip or wire which has beenheated [UNITED STATES'PATENT O F 10 form of welding electrodes and current conductin thecontr'olled atmosphereis quenched in oil 10 30 sectional area are particularly sensitive to intering b s In fa r ating t alloys a heat the freedom from intergranular oxidation is treatment is employed to effect pre ip maintained. However, the physical properties hardening This treatment consists in heating of the alloy quenched in oil are inferior to the the 3110575 to a temperature of about properties obtained with a saltwater quench. l5 efiect a solid solution condition in the alloy, the alloy is quenbhed in water to which is quenching and thereafter reheating or drawing has been added saltsolution acts to break the alloy 81 1.450 C- to 550 C. 130 efiect 8. cQndiy p r hi othefwise form tion of preclp ta o 1n the 3 on the surface of the not metal whenfit -is In heating alloys temperames above plunged into the cooling medium and thereby 9 11am amount mtergmmnar prevents any. intergranular oxidation during takes i such oxidatmn generally is quenching. After quenching from the solution gfigfl $fi f g m$ stock, g: temperature the alloy wire or strip may be prefi fi when that is nec 23 be cipitation hardened by reheating or drawing at my the usual elevated temperatures but not mate- 25 25 i s gg thereby m the rially higher-than 500 c. and for the usual peggq g 13 mi fig mxg ggfi riods of time necessary to effect the condition of precipitation in the alloys. Ifthe draw or rewhen these alloys are in the form of .strip or wire since the latte awm to their small 61.655 heat iscarried out in air the alloy strip or wire r g should be pickled thereafter to remove any scale granular oxidation. when such a condition exformed during the draw or reheat- Th alloys is'ts in the wire or strip alloys they crack severel may be cooled from the reheat temperature in air when bent thereby rendering the material useless or in, gaseous atmospheres which ordinarily prefor purposes such as springs and thelike. vent scaling at, 500 C. Any scale which may be One of the objects of the present invention is formed during "the draw is not accompanied by 35 to provide means for. preventing intergranular intergranular oxidation, since the latter occurs oxidation in alloys, in strip or wire form, which only at temperatures above 500 C. consist of 99 cobalt and beryllium D- What I claim as new and desire to secure by D chromium and beryllium- Letters Patent 0! the United States is:

.40 carryi out the P inventionthe The method of preventing intergranular oxidal w ar heated a h f r at a temperature tion in wire or strip ternary alloys consisting of about 900C. and for a period of time sumcient copper beryllium and m from t group to effect a solid s u i c nd in the alloys ball; and chromium which comprises heating said but the heating, t ry t0 former P alloys to an elevated temperature in an atmoslce, i ca out in Protective l' phere free from oxygen, water vapor and carbon free from oxygen, carbon dioxide and water vadioxide to thereby eflfect a solid solution condipor. The alloy strip 91 w 1 h quenched tion inthe alloy and quenching said strip or wire from the solu ion mp u T 111 1 8 from said temperature in a salt solution. medimnmaybeoilbutmoreaatlsiactoryresults r p sofialgtalnedbyq ench tinamiisal m 'mcmansnnmamc-ron u n. c 

